Fractal dimension of large aggregates under different flocculation conditions

Detalhes bibliográficos
Autor(a) principal: Moruzzi, Rodrigo B. [UNESP]
Data de Publicação: 2017
Outros Autores: de Oliveira, André L. [UNESP], da Conceição, Fabiano T. [UNESP], Gregory, John, Campos, Luiza C.
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional da UNESP
Texto Completo: http://dx.doi.org/10.1016/j.scitotenv.2017.07.194
http://hdl.handle.net/11449/169978
Resumo: The two-dimensional fractal dimension (Df) of large aggregates of kaolin (> 540 μm) during the shear flocculation process for kaolin solution was investigated using non-intrusive in situ image-based acquisition system. Separate experiments were also carried out for three different sized sub-ranges of large aggregates (0.540–1.125 mm; 1.125–1.750 mm; 1.750–2.375 mm). Digital images were taken at a frequency of 10 Hz for 10 s for each different pairs of gradients of velocity (Gf) of 20 and 60 s− 1 and flocculation times of 2; 3; 4; 5; 10; 20; 30; 60; 120 and 180 min. For the same conditions, particle size distribution (PSD) was also determined. Under the investigated conditions, the lowest Gf produced the greatest Df (1.69) at a flocculation time of 30 min for the whole range of aggregates. Also, the evolution of the longest length of aggregate (l) and Df with time, showed that the dynamic steady-state was reached at different times for each shear rate and l ranges. However, Df varied for each size sub-range (ca. 1.1 to 1.8). Finally, the behavior of the aggregate structure may be understood by the predominance of different aggregation mechanisms such as cluster-cluster for Gf of 60 s− 1 and particle-cluster for Gf of 20 s− 1.
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spelling Fractal dimension of large aggregates under different flocculation conditionsAggregatesFlocculationFractal dimensionShear rateThe two-dimensional fractal dimension (Df) of large aggregates of kaolin (> 540 μm) during the shear flocculation process for kaolin solution was investigated using non-intrusive in situ image-based acquisition system. Separate experiments were also carried out for three different sized sub-ranges of large aggregates (0.540–1.125 mm; 1.125–1.750 mm; 1.750–2.375 mm). Digital images were taken at a frequency of 10 Hz for 10 s for each different pairs of gradients of velocity (Gf) of 20 and 60 s− 1 and flocculation times of 2; 3; 4; 5; 10; 20; 30; 60; 120 and 180 min. For the same conditions, particle size distribution (PSD) was also determined. Under the investigated conditions, the lowest Gf produced the greatest Df (1.69) at a flocculation time of 30 min for the whole range of aggregates. Also, the evolution of the longest length of aggregate (l) and Df with time, showed that the dynamic steady-state was reached at different times for each shear rate and l ranges. However, Df varied for each size sub-range (ca. 1.1 to 1.8). Finally, the behavior of the aggregate structure may be understood by the predominance of different aggregation mechanisms such as cluster-cluster for Gf of 60 s− 1 and particle-cluster for Gf of 20 s− 1.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Estadual Paulista (UNESP) Instituto de Geociências e Ciências ExatasDepartment of Civil Environmental and Geomatic Engineering University College LondonUniversidade Estadual Paulista (UNESP) Instituto de Geociências e Ciências ExatasFAPESP: 2013/01634-3FAPESP: 2013/21355-1FAPESP: 2013/25641-9FAPESP: 2010/50694-0Universidade Estadual Paulista (Unesp)University College LondonMoruzzi, Rodrigo B. [UNESP]de Oliveira, André L. [UNESP]da Conceição, Fabiano T. [UNESP]Gregory, JohnCampos, Luiza C.2018-12-11T16:48:33Z2018-12-11T16:48:33Z2017-12-31info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article807-814application/pdfhttp://dx.doi.org/10.1016/j.scitotenv.2017.07.194Science of the Total Environment, v. 609, p. 807-814.1879-10260048-9697http://hdl.handle.net/11449/16997810.1016/j.scitotenv.2017.07.1942-s2.0-850264766002-s2.0-85026476600.pdfScopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengScience of the Total Environment1,546info:eu-repo/semantics/openAccess2023-10-18T06:07:03Zoai:repositorio.unesp.br:11449/169978Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T15:15:01.726870Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false
dc.title.none.fl_str_mv Fractal dimension of large aggregates under different flocculation conditions
title Fractal dimension of large aggregates under different flocculation conditions
spellingShingle Fractal dimension of large aggregates under different flocculation conditions
Moruzzi, Rodrigo B. [UNESP]
Aggregates
Flocculation
Fractal dimension
Shear rate
title_short Fractal dimension of large aggregates under different flocculation conditions
title_full Fractal dimension of large aggregates under different flocculation conditions
title_fullStr Fractal dimension of large aggregates under different flocculation conditions
title_full_unstemmed Fractal dimension of large aggregates under different flocculation conditions
title_sort Fractal dimension of large aggregates under different flocculation conditions
author Moruzzi, Rodrigo B. [UNESP]
author_facet Moruzzi, Rodrigo B. [UNESP]
de Oliveira, André L. [UNESP]
da Conceição, Fabiano T. [UNESP]
Gregory, John
Campos, Luiza C.
author_role author
author2 de Oliveira, André L. [UNESP]
da Conceição, Fabiano T. [UNESP]
Gregory, John
Campos, Luiza C.
author2_role author
author
author
author
dc.contributor.none.fl_str_mv Universidade Estadual Paulista (Unesp)
University College London
dc.contributor.author.fl_str_mv Moruzzi, Rodrigo B. [UNESP]
de Oliveira, André L. [UNESP]
da Conceição, Fabiano T. [UNESP]
Gregory, John
Campos, Luiza C.
dc.subject.por.fl_str_mv Aggregates
Flocculation
Fractal dimension
Shear rate
topic Aggregates
Flocculation
Fractal dimension
Shear rate
description The two-dimensional fractal dimension (Df) of large aggregates of kaolin (> 540 μm) during the shear flocculation process for kaolin solution was investigated using non-intrusive in situ image-based acquisition system. Separate experiments were also carried out for three different sized sub-ranges of large aggregates (0.540–1.125 mm; 1.125–1.750 mm; 1.750–2.375 mm). Digital images were taken at a frequency of 10 Hz for 10 s for each different pairs of gradients of velocity (Gf) of 20 and 60 s− 1 and flocculation times of 2; 3; 4; 5; 10; 20; 30; 60; 120 and 180 min. For the same conditions, particle size distribution (PSD) was also determined. Under the investigated conditions, the lowest Gf produced the greatest Df (1.69) at a flocculation time of 30 min for the whole range of aggregates. Also, the evolution of the longest length of aggregate (l) and Df with time, showed that the dynamic steady-state was reached at different times for each shear rate and l ranges. However, Df varied for each size sub-range (ca. 1.1 to 1.8). Finally, the behavior of the aggregate structure may be understood by the predominance of different aggregation mechanisms such as cluster-cluster for Gf of 60 s− 1 and particle-cluster for Gf of 20 s− 1.
publishDate 2017
dc.date.none.fl_str_mv 2017-12-31
2018-12-11T16:48:33Z
2018-12-11T16:48:33Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://dx.doi.org/10.1016/j.scitotenv.2017.07.194
Science of the Total Environment, v. 609, p. 807-814.
1879-1026
0048-9697
http://hdl.handle.net/11449/169978
10.1016/j.scitotenv.2017.07.194
2-s2.0-85026476600
2-s2.0-85026476600.pdf
url http://dx.doi.org/10.1016/j.scitotenv.2017.07.194
http://hdl.handle.net/11449/169978
identifier_str_mv Science of the Total Environment, v. 609, p. 807-814.
1879-1026
0048-9697
10.1016/j.scitotenv.2017.07.194
2-s2.0-85026476600
2-s2.0-85026476600.pdf
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv Science of the Total Environment
1,546
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 807-814
application/pdf
dc.source.none.fl_str_mv Scopus
reponame:Repositório Institucional da UNESP
instname:Universidade Estadual Paulista (UNESP)
instacron:UNESP
instname_str Universidade Estadual Paulista (UNESP)
instacron_str UNESP
institution UNESP
reponame_str Repositório Institucional da UNESP
collection Repositório Institucional da UNESP
repository.name.fl_str_mv Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)
repository.mail.fl_str_mv
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